Inmotion device not transferring co-ordinates to stationary

We have in-motion devices in our vehicles and the data terminal program its connected to via serial cable is showing co-ordinates that update when travelling, however when the vehicle is stopped the co-ordinates stop transmitting and take a couple of minutes to start working again once the vehicle is moving again, any ideas how to tell in-motion to constantly update over the serial cable even if it is transferring the same co-ords over and over again to a stationary vehicle.

We have tried this system with a $40 gps puck and that works so in motion should be able to?

Thank you

If you tell me about the device you are using, I can refer this topic to the correct section.